Editor—Congenital disorders of glycosylation (CDG) are a heterogeneous group of autosomal recessive multisystemic conditions causing severe central nervous system and multivisceral disorders resulting from impairment of the glycosylation pathway.1-3 Two disease causing mechanisms have been identified so far. CDG I is caused by a defect in the assembly of the dolicholpyrophosphate oligosaccharide precursor of N-glycans and its transfer to the peptide chain, while CDG II results from a defect in the processing of N-glycans.3 CDG I and II have distinct patterns of abnormal glycosylation depending on the reduction of the glycan chain number or its structure. CDG I, the most frequent form, is the result of different enzyme deficiencies: phosphomannomutase (CDG Ia), phosphomannose isomerase (CDG Ib), and glucosyltransferase (CDG Ic).3-6 CDG IIa is characterised by a defect in N-acetylglucosaminyltransferase II and only two cases have been reported previously.7-11 Here, we report a new case of CDG IIa sharing a number of clinical features with the two previously reported cases and emphasising the clinical differences from CDG I.

A boy was born at term to unrelated, healthy parents after a normal pregnancy and delivery, birth weight 3050 g, length 48 cm, and OFC 35 cm. At 3 months of age, hypotonia, feeding difficulties, and diarrhoea were noted. A milk protein intolerance was suspected and he was put on a milk free formula until the age of 4 years. He was first referred to our …